5 Neurogenic VD Flashcards
(18 cards)
Anatomical pathway (+innervation) of SLN
- Internal branch: sensory info
- External branch: motor info (provides innervation to the cricothyroid muscle; pitch control)
Anatomical pathway (+innervation) of RLN
- Loops around the heart
- More prone to injury
- Provides motor (check) innervation to all the intrinsic muscles except for the cricothyroid
Vocal Fold Paralysis
(1) Prevalence
(2) Types
(3) Cause(s)
- Most common neurogenic voice disorder
- Proximal [closer to brain] vs. distal lesions
- Usually caused by peripheral involvement of the RLN [more prone to injury]
- Less frequent cause: Peripheral lesions of the SLN
Vocal Fold Paralysis
(4) Voice quality
- The location of the lesion along the pathway will determine the type of paralysis and the resultant voice quality
Vocal Fold Paralysis
(5) Etiologies
- Surgical trauma
- Cardiovascular disease
- Neurological disease
- Mechanical trauma
- Idiopathic onset (often following viral infections) –> unusual but happens
Nature of Peripheral Paralysis + Implications
- Peripheral nerve damage causes paralysis that is flaccid in nature [no instructions from CNS; nerve will send random commands i.e., fasciculations]
- Flaccid paralysis leads to loss of intrinsic muscle tone and atrophy of muscle tissue
[over time the muscle will convert to fat and be sent to the lymphatic system]
Adductor vs. Abductor Paralysis
(Low peripheral paralysis + role of cricothyroid)
- Low peripheral paralysis: either the SLN or RLN cut off individually
Isolated supralaryngeal nerve paralysis: Leads to isolated CT paralysis; laryngeal asymmetry (VF would still work, but cricothyroid will not be able to stretch VF as much)
Isolated recurrent nerve paralysis: Paralyzed vocal fold rests in paramedian or abducted position (cricothyroid is still pulling on the VFs which results in VFs coming twd the middle)
Adductor vs. Abductor Paralysis
(High peripheral paralysis + implications on voice)
- Combined recurrent and supralaryngeal nerve
paralysis: Vocal fold rests in abducted position - Higher lesion in the neck above SLN and RLN
- Patient may experience aphonia [wider abduction, harder to compensate]
- Swallowing may be impacted (aspiration may occur)
5 Positions of paralyzed VFs
- Median (fully adducted)
- Paramedian
- Intermediate
- Abducted
- Wide abducted
Bilateral Abductor Paralysis
(1) Position of VFs
(2) Severity
(3) Frequency
(4) Implications on phonation and respiration
(5) Etiology/cause
- Both VFs are paralyzed in the adducted position [one VF can be higher than the other; an arytenoid may collapse over the other]
- The most severe form of VF paralysis
- Relatively infrequent compared to unilateral paralysis
- May severely compromise respiration [tracheotomy req for breathing]
- Vocal function and airway protection are usually good
- Can be caused by thyroid cancer surgery
Bilateral Abductor Paralysis
(6) Therapy
- Tracheotomy, if necessary
- Phonosurgery: lateral suturing or complete removal of one arytenoid opens the airway (increases risk of aspiration during swallowing + vocal function deteriorates)
- Post-operative voice and swallowing therapy to restore vocal function and prevent aspiration
Bilateral Adductor Paralysis
(1) Position of VFs
(2) Implications on phonation and respiration
- Both VFs are frozen in the abducted position
- Good respiration
- Poor phonation or complete aphonia
- High risk of aspiration: gastrostomy tubes are necessary in many patients
Bilateral Adductor Paralysis
(3) Therapy
- Nasogastric or Percutanous Endoscopic Gastrostomy (PEG) feeding tube if condition lasts long
- Augmentative communication devices: electrolarynx, speech amplification systems [due to aphonia]
- Fibrosis and contraction of the glottis starts 6-9 months post onset and can reduce the glottal opening considerably (one VF might come a bit more medially over time due to fibrosis and contraction)
- This approximation of the vocal folds facilitates breathy, hoarse phonation and increases airway
protection but may decrease the air passage
Unilateral abductor paralysis
(1) Position of VFs
(2) Implications on phonation and respiration
(3) Voice quality
- The paralyzed fold remains in the median or paramedian position
- Usually relatively good respiration, phonation & protection against aspiration because of the fully functional contra-lateral fold
- The flaccid paralysis of the affected fold will decrease the patient’s dynamic range
- The airway diameter is reduced which may lead to inspiratory stridor during heavy physical activity
Unilateral abductor paralysis
(4) Therapy
- Not much therapy needed
- Voice therapy to increase dynamic range
Unilateral adductor paralysis
(1) Position of VFs
(2) Frequency
(3) Implications on phonation and respiration
(4) Voice quality + range
- The most common type of VF paralysis
- The paralyzed fold is frozen in intermediate, abducted or wide abducted position
- The position and vertical height of the abducted fold and the resulting gap determine the severity of the resulting voice disorder
- Voice quality is breathy and can be diplophonic
- Vocal intensity and range are decreased
- Patients complain of physical fatigue bc of increased vocal effort
Unilateral adductor paralysis
(5) Therapy
- Voice therapy (vocal function exercises, voice projection)
- Phonosurgery (injecting under TA muscle, cutting window in thyroid cartilage + putting a silicon wedge –> better closure, swallowing, voice)
